Frame rails of a motor vehicle body are typically connected with each other by one or more cross members in the rear of the body, to form a closed rear or back frame. The position of the cross member varies when viewed in the longitudinal direction of the vehicle, and adjusted to the respective motor vehicle configuration or the motor vehicle type. For example, depending on whether the motor vehicle is to be equipped with a trailer/towing device or an extendible load carrier, this may require that corresponding changes be made to the design of the vehicle body, in particular with respect to the position of the cross member. This holds true in equal measure for different vehicle types, for example for sedans or caravans or station wagons or limousines.
In addition, new drive concepts for vehicles, in particular for hybrids or fuel-cell powered vehicles, require a modified or variably adjustable partitioning of the installation space for accommodating energy storage modules or fuel containers. In particular for hybrids or purely electric-powered vehicles, it is desirable to incorporate the batteries they require as deeply as possible in the vehicle, to improve the center of gravity of the vehicle. For example, DE 10 2007 047 037 A1 discloses a motor vehicle body with two opposing rear side frame rails, wherein at least one auxiliary frame and/or one or more cross members can be allocated to the rear side frame rails and secured thereto.
The side frame rails, the auxiliary frame or the cross members are here already provided in advance with a number of joints, which are designed and arranged in such a way that one or more correspondingly adjusted aggregates and/or add-on parts can be modularly secured to the side frame rails in proximity to the joints, depending on the equipment currently desired for the motor vehicle rear frame. It is complicated and costly from the standpoint of production and assembly to have available a plurality of different body variants, e.g., in which sheet metal parts for the body must be separately fabricated and conceived for each type of vehicle. In addition to the body structure, motor vehicles exhibit a chassis, which is fabricated parallel to the body in the process of manufacturing the motor vehicle, and joined in its entirety with the preconfigured body in a joining process generally referred to as a marriage. In particular, in the rear area, the chassis exhibits a wheel suspension with lateral, pivoted axle journals, wherein the left and right axle journals are typically coupled by means of a Watt linkage.
In known vehicle configurations, the Watt linkage is mounted on load-bearing structural components of the body, or pivoted thereto. In this way, a Watt linkage coupling is established in the area of a cross member structure that joins the two frame rails of a motor vehicle body in the transverse direction (y) of the vehicle. A plurality of individual assembly steps involving the use of several components is required precisely for attaching and assembling a Watt linkage to the body.
Therefore, at least one object is to provide a rear cross member of a motor vehicle body that is improved in terms of weight and installation variability, and distinguished by both lower production and assembly costs and a reduced weight. At least another object is to create a rear vehicle platform-independent rear cross member structure that can be individually adjusted to different vehicle types and equipment, and is easy to assemble. In addition, the process of joining the motor vehicle body and chassis is to be simplified and optimized, while economizing on assembly steps and reducing the number of components required for assembly. In addition, other objects, desirable features, and characteristics will become apparent from the subsequent summary and detailed description, and the appended claims, taken in conjunction with the accompanying drawings and this background.